For every human cell in your body, there are hundreds or thousands of bacterial cells. So who is hosting whom? Even though our on-board microbial hordes—known also as our microbiome—sometimes threaten and deprive us of our health and our lives, they are central to our survival and our daily well being.

Join a live-streaming discussion brought to you by the DC Science Writers Association and the USA Science and Engineering Festival on Tuesday, April 17 from 6:30 to 8:30 p.m., ET, from Busboys and Poets on 5th and K Sts., NW, Washington, D.C., that might convince you to love your microbial partners in life, albeit with a healthy respect for the ways they can become dangerous. Leading the discussion will be microbiologist Liliana Losada of the J. Craig Venter Institute, an independent research laboratory in Rockville, Md., that has been greatly expanding our fundamental knowledge of the microbes in our world; and Alison O’Brien, former president of the American Society of Microbiology, professor of microbiology and immunology at the Uniformed Services University of the Health Sciences, and an expert in the gut bacterium known as E. coli, a major player in human health, basic science and biotechnology.